PEST MANAGEMENT DECISION GUIDE: GREEN AND YELLOW LIST
Serpentine leaf miner on beans
Liriomyza species, Likely L trifolii, L. sativae
- Use tolerant crop varieties such as Lukupa or Kabulangeti
- Where possible, cover small plants with transparent plastic (such as polytunnels) to prevent insects from laying eggs.
- Weed out leguminous plants which can be alternative hosts such as sweet clover, Lathyrus, and many others.
- Plant maize around beans because maize acts as a barrier against the leaf miners
- Rotate beans with cereals, and not with legumes, tomatoes, garlic, onions, groundnut, rape, melon or cucumber.
- Monitor weekly at all growth stages of crop.
- Look for tiny thread -like tunnels (mines) on the upper leaf sides.
- Look for larvae inside tunnels or on the upper side of leaves (tiny legless maggots with no separate head, whitish transparent and later yellow-orange)
- Threshold: At 8 to 12 infected plants (with 5-6 infected leaves) per 100 plants, consider green direct control action.
- If, after green direct control, leaf miner damage still increases up to 20 to 30 infected plants per 100 plants, then consider chemical action.
- Hand pick heavily infested leaves with many leaf miner tunnels, and destroy them by crushing or burying them, or feeding them to cattle.
- Spray neem extract against larvae onto leaves in the early morning or late evening. Add a sticker such as liquid soap to the neem water mix. Reach good leaf coverage. Neem slightly enters the leaves and reaches some of the larvae inside the tunnel.
- If possible cover soil under infested plants with plastic sheets to prevent larvae from reaching the ground and pupating
- When using a chemical pesticide or botanical pesticide, always wear protective clothing and follow the instructions on the product label, such as dosage, timing of application, pre-harvest interval, max number of sprays, restricted re-entry interval. Do not empty into drains and water sources.
- WHO toxicity class II pesticides might not be allowed in local IPM schemes.
- Always consult recent list of registered pesticides of ZEMA
Dimethoate - based products, (Sinothoate, Dimethoate 40EC, and others) against leaf miner larvae. Contact and systemic organophosphate group of pesticide, IRAC insecticide Group 1B.
WHO toxicity class II (moderately acute hazardous); Maximum 2 sprays per season at vegetative stage in min 2 week interval; pre-harvest interval p.h.i. 14 days.; restricted re-entry interval r.e.i. 3 days after spray; Broad spectrum pesticides that kill many natural enemies. Toxic to pollinators, soil organisms like earthworms, and fish. Double-check recent laws whether this pesticide is still allowed in IPM
Imidacloprid - based products. Usually used at 200g/L but double-check labels. (Premise 200SC, Amigo GT, Ngenya T450 FS , and others) Systemic neonicotinoid insecticide group IRAC 4.
WHO Class II (Moderately hazardous). Max 2 sprays per season at min 7 day interval. p.h.i. 14 days, r.e.i. 3 days. Highly toxic to pollinators such as bees, thus do not spray on flowering crop, and not when weeds are flowering and not near bee hives.
CREATED/UPDATED: October, 2015
PRODUCED BY: Plantwise
©CAB International. Published under a CC-BY-SA 4.0 licence.